Rice is life for almost half of the global population and majority of the Indian people. The living and livelihood of majority of the Indian farming population also depends on growing rice. Rice production increased almost three fold over the last five decades and contributes handsomely to the nutritional security of the country. While green revolution brought productivity increase and regional food surpluses as far as rice is concerned and it also created huge negative environmental footprints. Climatic change casts a huge shadow in the horizon of agricultural productivity.
Further, there are reports that erratic monsoon behavior also affects the grain production, especially in rainfed areas which occupy 62% of the total rice area of the country. A variety of factors including (i) declining yields and less land, water and labor (ii) effects of economic growth (iii) pressure on land use, and (iv) climate change, threatens future rice production. While on the brighter side, rice contains a tremendous array of genetic diversity that scientists have only just begun to explore. And this huge genetic diversity also empowers rice to remain productive in environments where most other crops would fail. Rice production systems are unique and the longevity of rice farming speaks for itself. In fact, given to itself, the overall environmental footprint for rice would remain only subtle.
- Biotic and Abiotic Stress factors affecting crop yield
Depending on the climatic conditions, traditional as well as semi-dwarf varieties suffer from various pests and diseases. Among pests yellow stem borer (Tryporyza incertulas), leaf folder (Cnaphal-chorosis medinals) and brown plant-hopper (Nilaparavatalugens) affect the crop to varying degrees. Bacterial leaf blight, blast, sheath blight and false smut not only reduce the gram yield but also severely impair the ‘grain quality. Necessary prophylactic measures, balanced nutrition and clean cultivation can help to reduce losses. Among the current new approaches viz. new plant type, hybrid rice and molecular techniques, hybrid rice approach seems to have potential as it gives minimum 10-15 % yield advantage over best commercially cultivated fixed variety. Despite hurdles on the seed front, hybrid rice is slowly but surely spreading across the country. Water is the most critical component of life support systems. In this context India shares about 16% of the global population but it has only 4% of the total water resource. The irrigation sector, which uses 83% of water, is the main consumer of this resource. The main water resources in India consist of precipitation on the Indian Territory – estimated to be around 4000 cubic kilometers per year (km3/year) – and Trans boundary flows, which it receives in its rivers and aquifers from the upper riparian countries.
- Impact of power of biotechnology to strengthen the rice productivity
Recent advances in functional genomics and bioinformatics have opened up new vistas to undertake customized genetic engineering, keeping intact other characters. While existing transgenic research is being strengthened and the field potential of the developed and developing lines is being tested through large-scale field testing, power of biotechnology would help in redesigning the rice plant for greater productivity for the future through (i) transgenic breeding for incorporation of genes for improving yield, resistance/tolerance against biotic/abiotic stresses and grain quality to cater to national and international markets, (ii) development of herbicide-tolerant transgenic rice as an input to direct-seeded rice growing under conservation agriculture, (iii) development of transgenic rice with nutrient acquisition properties like P-uptake and utilization and mining of essential macro- and micronutrients with genes sourced from the microbial world.
- Hybrid rice research leads to jump overall rice production
There are reports which indicate that the, the hybrid rice is expected to give a quantum jump to overall rice production in India in the coming decades. Although rice hybrids developed by public and private sectors have made some progress in irrigated areas of semi-arid to sub-humid regions, the yield realization need to be enhanced through increased heterosis as well as introgressing known pest and disease tolerance genes in the parents. Further, there is also need to develop hybrids for rainfed lowlands of high rainfall areas. The yield potential of hybrids for such situation needs to be enhanced by increasing the degree of heterosis through envelopment of suitable parental lines. Efficient and economic hybrid seed production is the key for the successful exploitation of hybrid rice in the country and more research effort is needed in this very important aspect of hybrid rice.
- Significance of Bio-fortification to enhance crop yield
In the recent years, the micronutrients deficiencies have presently become one of the major constraints in sustaining crop production in the present intensive agriculture. While it is indispensable to use the micronutrient fertilizers for sustaining high crop yields and maintaining quality for efficient to these fertilizers materials to overcome/ameliorate the deficiencies. Field scale Zinc (Zn) deficiency was first noticed in rice in tarai soils of Uttar Pradesh and in wheat on sandy soils of Punjab. Deficiency of iron in rice, sugarcane and groundnut crops on sandy soils.
Well, zinc is essential for survival and is known to be required for more body function than any other mineral while iron deficiency is known to retard physical growth and mental development of children. Iron deficiency anemia is a major cause of women’s death during child birth among the poor population. Biofortified foods including rice can reach millions of malnourished rural population who generally have limited access to commercially marketed fortified foods and supplements. CRRI has identified rice germplasm containing more than 20 ppm Fe and more than 50ppm Zn in unpolished rice that are being used in the breeding program with a view to develop iron/zinc rich high yielding rice varieties. It has been observed that Transgenic approaches incorporating ‘ferritin’ gene for Fe and genes for carotenoids driven by endosperm specific promoters could be a better solution for developing lines with high Fe or pro-vitamin A.
- Transgenic Rice- a new approach to stabilise and nutritionally rich rice production
Over the last two decades humanity has acquired biological knowledge that allows it to tamper with the very nature of creation. It is now, only at the beginning of a process that will transform our lives and societies to a much larger extent than all inventions of the last decade. Biotechnological developments are poised to complement and speed up the conventional rice improvement approaches in many areas which could have immediate and long term impacts on the rice yield ceiling, stabilizing the productions and making rice nutritionally superior. The genetic engineering tools could be used to introduce superior kind of plant resistance through wide hybridization, another culture, marker aided selection, and transformation. These tools and tagging of quantative trait loci would help enhance the yield potential. Rice transformation enables the introduction of single genes that can selectively perturb yield determining factors.
- Developing of C4 rice to increase rice yield
According to the reports, it has been observed that rice and wheat assimilate atmospheric CO2 by the less-efficient C3 pathway of photosynthesis and at the same time lose net carbon gain and productivity by as much as 40% through photorespiration. This renders C3 plants less competitive to crops like maize and sugarcane that have evolved a biochemical “CO2 pump” – the C4 pathway of photosynthesis, to concentrate atmospheric CO2 in the leaf and overcome photorespiration. Construction of C4 rice in which the 3-carbon metabolic pathway of photosynthesis as present in rice plants is converted into a C4 one is a blue-sky research concept. C4 rice is expected to increase rice yields dramatically, as high as 50%, independent of the rice-growing environment while using water or fertilizer up to 30% more efficiently. Thus, our research work envisages engineering the C4 traits in rice to enhance its productivity. While the metabolic components already exist in C3 rice plants, the anatomical and biochemical features of C4 plants must be understood and transferred to C3 plants. The C4 photosynthetic system has given us the indication that it may be experimentally feasible to genetically engineer all C4 genes in single cell of C3 plants i.e. rice to enhance its photosynthetic activity and productivity. This may lead to improved CO2 concentrating mechanism in a single cell favoring carboxylation and thus C4-ness.
In the view to enhance and to assess critically the rice production and climate changes, it has been noted the global climate change has potential for grave consequences because of its potential threat to rice productivity and, consequently food security. Land-use systems in India are highly vulnerable to climate change and have only marginal capacity to withstand its impact. Conditions for rice production will deteriorate in many parts of India through water shortages, low water quality, thermal stress, floods and in the coastal areas, sea-level rise and more intense tropical cyclones. A 15% decrease in irrigated rice yields in developing countries and a 12% increase in rice price is anticipated as a result of climate change by 2050.
Dr. Sujata Pandit Sharma
Head (R&D) & PIC (IGNOU)
FICCI research and Analysis Centre, India